Framebuilders - reveted water bottle bosses

I understand there are bosses that function like rivets. I would like to drill holes in my seat tube for water bottle bosses and do not want to mess with brazing and repainting. Anyone know about this, or who can supply them? Thanks.

They are called "Rivnuts". Do a Google search to find more information. Contrary to popular opinion, you do NOT need to buy a special tool to install them although the tool does make installation easier. MANY OE frames come with Rivnuts, including Cannondale, so a good LBS should have a stock of them.

FWIW, I've installed them in a couple of frames with fine results.

Good luck.

Ed

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Wicks aircraft sells the rivnuts and a pop rivet gun tool for installation that is quite inexpensive. They are not metric using a 10/32 screw but I've been satified with it.

Tom P

They are called "Rivnuts". Do a Google search to find more information. Contrary to popular opinion, you do NOT need to buy a special tool to install them although the tool does make installation easier. MANY OE frames come with Rivnuts, including Cannondale, so a good LBS should have a stock of them.

FWIW, I've installed them in a couple of frames with fine results.

Good luck.

Ed
Thanks for the information.

McMaster-Carr has them in both english and metric sizes, look up "rivet nut" from their main page.

Hi all... I'm resurrecting this thread because I'd like to install two sets of bottle braze-ons onto my early-80s Fuji Allegro frame. It's a very nice frame other than the lack of bottle braze-ons.

I see the McMaster rivnuts here: http://www.mcmaster.com/param/dsc/dsc.aspx?dsc=Rivet+Nuts&WRQuickLinks=Rivet+Nuts
There's quite a variety of them. Which kind would work best as bottle braze-ons?

I found a thread on rivnut installation (http://www.bikeforums.net/archive/index.php/t-26735.html) in the archive, where Rev. Chuck sez:
you can install a rivnut without the special tool by using the correct size nut and bolt. Thread the nut on to the bolt and thread the bolt fully in to the riv nut. Insert the riv nut into the frame and crank the nut down on to the riv nut while pushing down on to bolt and preventing it from turning. Used to work for a Cdale dealer and we had to do this on some of the smaller frames, that the plier style tool would not fit into.

On the other hand, some experts like Jobst Brandt argue in this thread (http://www.cyclingforums.com/t24272.html) that rivnuts will weaken a frame. What do you guys think?

If I get rivnuts for M5 bolts, what is the appropriate diameter hole to drill in the frame? Should any kind of epoxy be used around the hole for extra secure/watertightness? Thanks for any advice!

If I get rivnuts for M5 bolts, what is the appropriate diameter hole to drill in the frame? Should any kind of epoxy be used around the hole for extra secure/watertightness? Thanks for any advice!Follow the instructions. It say what size hole to drill.
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Wicks aircraft sells the rivnuts and a pop rivet gun tool for installation that is quite inexpensive. They are not metric using a 10/32 screw but I've been satified with it.

Tom PA metric 5x0.8mm bolt fits just fine in the 10/32 hole. :) You can also spin down a long bolt so that its shank fits into a standard pop-rivet tool. Leave about 10mm of threads at the end to go into the riv-nut and >POP< it's in! :) I've always like to use a little epoxy on both sides of the hole to at least seal against water. I doubt the hole will cause much of a problem structurally since most frames aren't built on the super-light at-the-limit edge anyway. You might reduce its lifespan from 300 to 100-years. You'll most likely crash and bend the top-tube or chain/seat-stays well before the downtube. :)

Follow the instructions. It say what size hole to drill. A metric 5x0.8mm bolt fits just fine in the 10/32 hole. :) You can also spin down a long bolt so that its shank fits into a standard pop-rivet tool. Leave about 10mm of threads at the end to go into the riv-nut and >POP< it's in! :) I've always like to use a little epoxy on both sides of the hole to at least seal against water. I doubt the hole will cause much of a problem structurally since most frames aren't built on the super-light at-the-limit edge anyway. You might reduce its lifespan from 300 to 100-years. You'll most likely crash and bend the top-tube or chain/seat-stays well before the downtube. :)
Thanks, Danno. Mine is Fuji VALite single-butted tubing, nothing insanely light, so there should be no structural problem. I was planning to drill the seat tube as well, hope that's not a problem.

That just leaves the one bewildering question... which of the many types of rivnuts do I buy? :)

That just leaves the one bewildering question... which of the many types of rivnuts do I buy? :)94020A375

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Thanks, SoonerBent. I see that's an aluminum M5 rivnut, with an open bottom. Is there a reason to choose aluminum over steel, given that the frame is steel?

Either steel or aluminum will work. I've always used Al because that's what I could swipe at work:)

One guy on the framebuilders list a while ago said that he had some old aluminum Rivnuts that had age hardened and were difficult to crimp. Bought some new steel ones and he was happy. Take it for what it's worth.

Either steel or aluminum will work. I've always used Al because that's what I could swipe at work:)

One guy on the framebuilders list a while ago said that he had some old aluminum Rivnuts that had age hardened and were difficult to crimp. Bought some new steel ones and he was happy. Take it for what it's worth.
Thanks for the info! I'm gonna see if I can get these locally, and if not go with McMaster.

Any time you drill a big holes and then load it, it isn't all that wonderful for the frame. It's not all that wonderful to heat the frame either, and I doubt braze will flange the hole to add back the strength. With motorcycle frames, the tubbing is pretty tough, and the "bungs" get welded in, which isn't a heat treating problem in CR. That makes for a tough assembly, unfortunately all we have with bikes is the hope the tube isn't critically weakened which is shouldn't be given the track record.

I would guess the seat post would be the least affected by drilling, and a water bottle on the outside of the downtube would be the worst. With the seatpost you just have to be careful not to get it in the way of the post, including any possible down position for shipping.

In terms of what material to use, would AL not be more favourable in terms of the galvanic series, the bung would corrode and not the tube, if the steel you chose happens to be lower the frame goes first. That's at least a consideration, though I may have the whole thing backwards.

You've got it right. Metals higher up on the galvanic series will corrode first. So an AL insert would go first in a steel frame. However, the degree of corrosion also makes a difference and the closer the metals are on the series, the less the corrosion. Steel riv-nuts are probably 1010/1020 mild-steel which is just slightly higher up the series than chromoly, so this would probably result in the least amount of galvanic corrosion with the riv-nut being the sacrificial part.

All this talk of weakening the tubes is making me hesitant... are two little 5/32" holes in the downtube really that dangerous? How are brazed-in bottle bosses any stronger?

Don't worry, it's not gonna weaken your bike at all. The braze-on bosses have a lip that's attached to the hole making the thickness around the hole thicker than the tubing by itself. If you epoxy the riv-nut in, that should serve a similar stiffening around the hole. On one of my old MTBs with thick tubing, I didn't even bother with an insert, I just drilled hole and tapped the tubing. The two threads were enough to hold a water-bottle cage. Still have that bike 10-years later, going on strong. :)